Checking tool for measuring distance between adjacent sinking grooves in inner hole of mechanical part

Abstract

A checking tool for measuring a distance between adjacent sinking grooves in an inner hole of a mechanical part, including: a gage block, end cover, sliding piece, pin, base, pin seat, support, measuring rod, spring, barrel, and dial indicator. An inner end face of the base is provided with the sliding piece, at least three concentric circular arc grooves are on the end face, paired eccentric arc grooves are on the sliding piece, the pin connected to the pin seat runs through the base and sliding piece, which is axially limited by the end cover, and the seat rotates relative to the base to realize radial expansion displacement of the sliding piece. A measuring head is formed by the dial indicator, measuring rod, spring and barrel. By positioning the edges of adjacent sinking grooves in an inner hole, measurement for a distance between the grooves is converted into depth measurement.

What is claimed is: 
     
       1. A checking tool for measuring a distance between adjacent sinking grooves in an inner hole of a workpiece, the checking tool comprising:
 a gage block, an end cover, a sliding piece, a pin, a base, a pin seat, a support, a measuring rod, a spring, a barrel, and a dial indicator, the checking tool enabling quantitative detection of an axial position of the gage block in the inner hole of the workpiece by the dial indicator, wherein: 
 the gage block (i) has a T-shaped side face, (ii) is disposed on a bottom end face in an inner hole of a workpiece and (iii) stops at an edge of an inner sinking groove, and on this basis, a distance from an outer sinking groove is measured; 
 the end cover, the base and the pin seat are all flange-shaped, and an outer circle of the end cover is in clearance fit with an inner hole of a measuring port portion of the workpiece; 
 at least three radial opening grooves are uniformly distributed on an end face, facing the inner hole of the workpiece, of the base, each radial opening groove being provided with a sliding piece; 
 concentric circular arc grooves paired with the radial opening grooves are also provided on the end face of the base; 
 an outer edge of the sliding piece is a circular arc edge, an outer convex edge is shaped for insertion into the outer sinking groove of the workpiece, and a clockwise eccentric circular arc groove corresponding to the concentric circular arc groove on the end face of the base is provided on a plate surface of the sliding piece; 
 the pin is a cylindrical pin, a cylinder segment of the pin runs down through the concentric circular arc grooves of the base and the eccentric circular arc groove of the sliding piece axially in sequence, the pin is in interference fit with the pin seat, the sliding piece slides radially and is axially limited by the externally-connected end cover, and the pin seat is driven to rotate relative to the base, such that the pin limits the sliding piece to cause the sliding piece to undergo radial displacement along a track of the eccentric circular arc groove; 
 the barrel is a slender pipe, the dial indicator is inserted into an upper pipe orifice, an indicator rod of the dial indicator is axially displaced under the control of the spring and the measuring rod both disposed in the barrel, a bottom end of the barrel is inserted into inner holes of the pin seat and the base, and axially stops at an upper end face of the sliding piece, and the measuring rod disposed in the barrel directly pushes against an upper end face of the gage block under the pushing of the spring. 
 
     
     
       2. The checking tool for measuring a distance between adjacent sinking grooves in an inner hole of a workpiece according to  claim 1 , wherein the height of the gage block is smaller than a distance between two adjacent sinking grooves in an inner hole of the workpiece to be measured by 1-2 mm. 
     
     
       3. The checking tool for measuring a distance between adjacent sinking grooves in an inner hole of a workpiece according to  claim 1 , wherein at least three axially-adjustable elastic supports are installed at an outer edge of the base, the supports are in elastic contact with the opening end face of the workpiece, and the supports are adjusted to make the bottom end face of the sliding piece higher than the bottom end face of the outer sinking groove in the inner hole of the workpiece to be measured by 0.5-1.0 mm under the condition of dead weight. 
     
     
       4. The checking tool for measuring a distance between adjacent sinking grooves in an inner hole of a workpiece according to  claim 1 , wherein the spring is a pressure spring. 
     
     
       5. The checking tool for measuring a distance between adjacent sinking grooves in an inner hole of a workpiece according to  claim 1 , wherein the concentric circular arc grooves on the end face of the base and the eccentric circular arc groove on the end face of the sliding piece are of the same shape, only the center of circle of the eccentric circular arc groove is biased clockwise, and the radial displacement of the sliding piece is 2-5 mm.